Analysis for combining ability in sunflower organogenesis-related traits

Abstract

There are few reports about the genetic control of the in vitro regeneration ability in sunflower. In an attempt to enlarge the knowledge in this area, 7 cytoplasmic male-sterile, 7 fertile inbred lines, and their hybrids, were evaluated for their organogenic response to in vitro tissue culture. Cotyledonary explants were grown in culture medium containing MS saline base, indol-3-acetic acid, and kinetin at 25 ± 2°C with a 12-h photoperiod for 36 days. A completely randomised design with 2 replications of 20 explants each per treatment was used. All genotypes showed differences in the regeneration percentage and in the number of shoots per total explant cultured (P < 0.01). Genetic differences among the hybrids were due to additive effects (P < 0.01) for the female and male parents, but also a dominant effect (P < 0.01) was found. Among the male inbred lines, there was a strong inhibiting effect on the regenerating capacity ascribed to the restorer-inbred lines. The Ñ 844A inbred line had the best general combining ability and specific combining ability for the traits evaluated, so it can be considered as a putative candidate for inclusion in a breeding program to improve organogenesis. In this set of data, the additive main effects and multiplicative interaction and site regression analyses were useful tools to interpret the genetic variation for organogenesis-related traits.